The present invention is concerned with a water filter unit which includes a main housing including a removable main filter cartridge, and it is intended primarily for domestic use to filter impurities out of tap water. The unit may be placed on a usual counter adjacent to the sink. The filter unit may conveniently be coupled to a diverter valve which, in turn, is connected to the sink water faucet. The diverter valve may be manually set for normal water flow from the faucet into the sink when it is in a first position, and for water flow through the filter unit of the invention when it is in a second position.
In the embodiment to be described, the filter unit of the invention is coupled to the diverter through a 90 degree elbow which is fitted into the inlet of the filter at its lower end for 360 degree rotational movement. This permits placement of the filter unit on either the left side or right side of the sink with a minimum length of connecting tubing.
The filter unit of the invention in the embodiment to be described is equipped with a pressure balanced 360 degree rotatable outlet housing, with an elongated spout being fitted into the outlet housing. The rotatable outlet housing, in turn, is mounted on an elongated fitting which extends into the interior of the filter. The subassembly is constructed to ensure smooth operation of the filter with or without water pressure in the system and to prevent the top of the filter from blowing off in the event off pressure buildup in the spout. The spout is equipped with a sani-tip and screen to provide a smooth, coherent stream of water without splatter.
A spring-loaded retaining ring is provided between the outlet fitting and the rotatable outlet housing to assure that the outlet housing rests firmly against the outer surface of the main housing of the filter unit to provide a smooth, constant friction bearing surface for the outlet housing as the spout is turned about the longitudinal axis of the filter, and to prevent the outlet housing from being pulled off the filter unit when the unit is carried by the top of the outlet subassembly.
Custom-designed sealing washers are provided with sealing ribs to create a leak-proof seal between the filtered and unfiltered water in the sealed filter unit and between the water within the filter unit and the outside world.
The filter unit of the invention, in the embodiment to be described, is also equipped with a pre-filter in the form of a removable and washable filter screen which extends around the main filter cartridge and which serves to prevent clogging of the main filter cartridge.
In summary, the counter top water filter unit is intended for domestic use to be placed adjacent to a sink and having an inlet at its lower end which is coupled to the sink faucet through a swivelly mounted 90 degree elbow capable of 360 degree rotation so as to facilitate the coupling of the filter to the faucet from either side. The filter unit includes a cylindrical-shaped carbon particle filter cartridge which has a longitudinal passage extending from one end to the other, and a removable pre-filter screen coaxial with the cartridge and surrounding the cartridge, both elements being removably mounted within a cylindrical filter housing, the housing being closed at its upper end and open at its lower end. The filter cartridge has an upper end cap and a lower end cap, with the upper end cap being spaced down from the closed top of the filter housing when the cartridge is in place. An outlet fitting is mounted between the upper end cap of the cartridge and the closed top of the filter housing, and extends through an opening in the closed top in coaxial relationship with the cartridge. The fitting has an internal passage communicating with the central passage of the cartridge. An outlet housing is rotatably mounted on the protruding end of the fitting and is secured to the fitting. A radially-extending elongated outlet spout is fitting into the outlet housing, and the spout is coupled to the passage which extends through the outlet housing. The spout and outlet housing are rotatable about the longitudinal axis of the filter. Water entering through the inlet in the lower end of the filter passes up into the filter housing and through the annular channel which surrounds the pre-filter screen. The water then passes through the pre-filter screen and through the filter cartridge. The resulting filtered water travels up the central passage of the cartridge and through the passage in the fitting to the outlet spout.